<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button id="start">start</button>
    <button id="stop">stop</button>
    <div id="result"></div>
    <script src="webworker.js"></script>
    <script>
        let startBtn = document.getElementById('start');
        let stopBtn = document.getElementById('stop');
        let result = document.getElementById('result')
        startBtn.addEventListener('click',startWorker,false);
        stopBtn.addEventListener('click',stopWorker,false);
        let w ;
        function startWorker() {
            if(typeof (Worker) !=='undefined') { // 浏览器嗅探  是否支持Worker功能
                if(typeof(W) == 'undefined') {  // 只能实例化一次
                    w = new Worker('webworker.js');
                }
                w.onmessage = function(event) {
                    result.innerHTML = event.data;
                }
            } else {
                result.innerHTML='sorry,your browser 不支持'
            }
        }
        function stopWorker() {
            if(w) {
                // 终止线程
                w.terminate();
            }
        }
    </script>
</body>
</html>